July 26, 2005

Canada issues warning on Viagra vision loss

TORONTO (Reuters) - Canada advised users of the erectile
dysfunction drugs Viagra, Cialis or Levitra on Tuesday to seek
"immediate medical attention" if they experience sudden vision
loss or other vision problems when taking the drugs.

Health Canada, the federal health ministry, also said in a
statement it was likely to change the product information for
the three popular drugs.

Earlier this month the U.S. Food and Drug Administration
approved new labeling to warn men about possible blindness from
Pfizer Inc.'s Viagra.

The U.S. warning labels also affect Cialis, sold by Eli
Lilly & Co. and Icos Corp., and Levitra, which is co-promoted
by GlaxoSmithKline and Bayer AG .

"Health Canada is advising individuals who use the drugs
Viagra, Cialis and Levitra to consult their physicians and seek
immediate medical attention if they experience sudden vision
loss or vision-related problems while taking these drugs," the
statement said.

Later, Health Canada's spokeswoman, Nathalie Lalonde, said
it was too early to say whether the agency's decision would be
similar to the FDA's.

"We anticipate that we will be in a position to make a
decision in terms of labeling changes within the next two to
three months," she said.

The ministry said it was reviewing two Canadian reports of
Viagra users who suffered a specific type of vision loss --
known as non-arteritic anterior ischemic optic neuropathy --
which has been linked to impotence drugs.

Health Canada said it did not know if the vision problems
outlined in the two reports were linked to the drugs.

The statement cited a March article in the Journal of
Neuro-Ophthalmology on 14 cases of Viagra users suffering the
rare eye condition, in which the blood supply to the optic
nerve where it enters the eye is interrupted. All the cases
involved other risk factors for the condition, including high
blood pressure.

"The March paper did send us a signal, raised an antenna,"
said Lalonde.

"We don't make our decision based on such information.
However it does bring it forward as something that needs to be
looked into a little bit further and that's what we are doing
at this point."

Health Canada said it has asked for more safety information
from the drug firms.

A spokeswoman for Pfizer said the company was "committed to
working with Health Canada to determine what label change needs
to be made with respect to serious eye conditions."

Likewise, Bayer and Eli Lilly said they were working with
Health Canada and would make changes to their labels upon
request.